Europlanet Science Congress 2021
Virtual meeting
13 – 24 September 2021
Europlanet Science Congress 2021
Virtual meeting
13 September – 24 September 2021
EPSC Abstracts
Vol. 15, EPSC2021-191, 2021
European Planetary Science Congress 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b

Lorenzo V. Mugnai1, Darius Modirrousta-Galian2,3, Billy Edwards4, and the ARES V team*
Lorenzo V. Mugnai et al.
  • 1Sapienza Università di Roma, Dipartimento di Fisica, Roma, Italy (
  • 2INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo, Italy
  • 3University of Palermo, Department of Physics and Chemistry, Via Archirafi 36, Palermo, Italy
  • 4Department of Physics and Astronomy, University College London, London, United Kingdom
  • *A full list of authors appears at the end of the abstract

We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (~500 K) Super-Earth (1.13 Re) that was obtained with the G141 grism (1.125 - 1.650 micron) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produce a precise transmission spectrum. We analysed the spectrum using the TauREx3 atmospheric retrieval code with which we show that the measurements do not contain molecular signatures in the investigated wavelength range and are best-fit with a flat-line model. Our results suggest that the planet does not have a clear primordial, hydrogen-dominated atmosphere. Instead, GJ 1132 b could have a cloudy hydrogen-dominated envelope, a very enriched secondary atmosphere, be airless, or have a tenuous atmosphere that has not been detected. Due to the narrow wavelength coverage of WFC3, these scenarios cannot be distinguished yet but the James Webb Space Telescope may be capable of detecting atmospheric features, although several observations may be required to provide useful constraints

ARES V team:

Quentin Changeat, Jeroen Bouwman, Giuseppe Morello, Ahmed Al-Refaie, Robin Baeyens, Michelle Fabienne Bieger, Doriann Blain, Amélie Gressier, Gloria Guilluy, Yassin Jaziri, Flavien Kiefer, Mario Morvan, William Pluriel, Mathilde Poveda, Nour Skaf, Niall Whiteford, Sam Wright, Kai Hou Yip, Tiziano Zingales, Benjamin Charnay, Pierre Drossart, Jérémy Leconte, Olivia Venot, Ingo Waldmann and Jean-Philippe Beaulieu

How to cite: Mugnai, L. V., Modirrousta-Galian, D., and Edwards, B. and the ARES V team: ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b, European Planetary Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-191,, 2021.